Polyethylene terephthalate,nylon and organic esters of cellulose dyedwith 5-(2-nitro-pranisylazo) barbituric acid

ABSTRACT

A colorfast strong yellow disperse dye is prepared by coupling 2-nitro-p-anisidine to barbituric acid to form 5-(2-nitro-panisylazo) barbituric acid, m. 305*-6*C. It dyes polyesters and organic derivatives of cellulose (including acetate and triacetate), and nylons in greenish yellow shades.

United States Patent McKa Au 28, 1973 POLYETl-IYLENE TEREPHTHALATE, [58] Field of Search 8/21 B, 21 C. 24. NYLON AND ORGANIC ESTERS OF 8/41 B, 41 C. 50; 260/154 CELLULOSE DYED WITH S-(2-NlTRO-P-ANISYLAZO) BARBITURIC [561 References CM ACID UNITED STATES PATENTS 2,140,538 12/1938 McNally et al. 8/50 [75] Invent 3? Edward McKay Mddlesex' 2,140,539 12/1938 McNally et al. 8/50 [73] Assignee: American Cyanamid Company, Primary Examiner-George F. Lesmes Stamford, Conn. Assistant Examiner-Patricia C. lves [22] Filed Mar 13 1972 Att0rneyJ0hn L. Sullivan [21] Appl. No.: 234,425 [57] ABSTRACT Related Appncafion i A colorfast strong yellow disperse dye is prepared by coupling Z-nitro-p-anisidine to barbituric acid to form [62] $222 1? I969 5-(2-nitro-p-anisy1azo) barbituric acid, m. 305-6C. lt

dyes polyesters and organic derivatives of cellulose (in- U Cl. 8/41 B 8/21 B 8/21 C eluding acetate and triacetate), and nylons in greenish 8/41, C 8/50, yellow shades. [51] Int. Cl. C09b 29/36, D06p 1/18 3 Claims, No Drawings I dye.

POLYETHYLENE TEREPIITIIALATE, NYLON AND ORGANIC ESTERS OF CELLULOSE DYED WITH S-(Z-NITRO-P-ANISYLAZO) BARBITURIC ACID H I NH is an excellent disperse yellow dye for dyeing polyesters, nylons, and acetate and triacetate fabrics and fibers. It dyes these fibers greenish-yellow shades of excellent strength and colorfastness when applied by known disperse dyeing procedures. This is a new and surprising discovery, for other dyes of comparable chemical structure have not shown this desirable combination of properties.

The new compound of my invention is prepared by coupling diazotized 2-nitro-p-anisidine to barbituric acid in aqueous medium in the presence of a buffer such as sodium acetate. The insoluble product is separated,washed with water, and preferably kept in the form of a paste, paste blend, or concentrated aqueous dispersion until used in the dyeing procedure. It is usually blended with one or more surfactants, or dispersants, and homogenized with water to which small amounts of additives are added, such as a preservative, germicide, and antifoam.

l have found that the 5-(2-nitro-p-anisylazo) barbituric acid of my invention is an outstanding disperse dye for the so-called Thermosolmethod, a high temperature dry heat fixation. method by which polyester containing fabrics, especiallypolyester-cotton fabrics, are dyed. It produces very strong greenish-yellow shades on polyester without dyeing thecotton. The latter is washed or scoured free of any trace of adhering in permanent press treatment, which is applied to a finished dyed garment of polyester/cellulosics such as polyester/cotton and polyester/rayons, the dye of my present invention shows no shade change. Stability of shade in permanent press operation is ,an important property and an advantage. Also, during the high temperature curing step in which there is a prolonged heating period, many disperse dyes sublime, resulting in weakening of color and staining of combined fibers or fabrics. The dye of this invention shows little or no sublimation under permanent press conditions. It is also stable in the presence of zinc nitrate, a preferred catalyst for curing, so there is no need to switch to a less favorable catalyst.

Sublimation fastness of the compound of this invention can be demonstrated by sandwiching dyed polyester fabric between undyed polyester fabric and cotton, and subjecting it to temperatures of about 422 to 437F. Many of the known azo yellow disperse dyes tend to sublime badly at these temperatures whereas the dye of this invention shows little or no sublimation.

Another exceptional property of the dye or compound of my present invention is its fastness to light. A comparison of its lightfastness with those of similar azo dyes is given in Example 4. These comparisons are for a medium 0.5 percent shade. Well known AATCC tests and ratings are used. The rating of 6 on polyester andacetate is very good. The rating on triacetate is also 6. The 2 percent shade has a rating of 6-7 by carbon-arc lamp, which is very-good-to-excellent, and a rating of 7 using a Xenon light source, which is excellent. This is surprising in view of the much lower lightfastness of other yellow azo dyes of the barbituric acid series.

The dye of this invention also has a high rating for colorfastness to washing, acid and alkaline perspiration, and to crocking, rating 5 for all. It also has very high tinctorial value which is both an important property and an economic ad-vantage.

Known yellow disperse dyes tend to be deficient in one or more of the above properties. It is surprising that this particular chemical compound has such outstanding fastness properties. It also has good general dyeing properties such as good dispersion, leveling, and migration properties.

The dye of this invention finds greatest use on polyester, polyester blends, and organic derivatives of cellulose such as acetate and triacetate. it also has affinity for nylons and relatively good lightfastness compared to known dyes on these polyamide fibers. It does not dye polypropylene fibers as currently modified.

The invention will be further described and illustrated by the following specific examples to which, however, it is not limited.

EXAMPLE 1 Preparation of 5-(2-nitro-p-anisylazo--barbituric Acid.

A suspension of 3.4 parts by weight of 2-nitro-panisidine in 30 parts of 10 percent of hydrochloric acid is prepared and cooled to 0C. in an ice bath with internal addition of ice. A solution of 1.4 parts of sodium nitrite in five parts of water is added slowly and the resulting mixture is stirred with cool-ing for one-half hour.

A mixture of 2.6 parts by weight of barbituric acid and 15 parts of sodium acetate in 50 parts of water is preparedand cooled to 0-5-C. The above-described diazonium solution is then added and the mixture is stirred for four hours, after which the resulting .5-(2- nitro-p-anisylazo)-barbituric acid is separated by filtration, washed with water, and dried in a vacuum at C. Recrystallization from ethanol results in a product melting at 305306C.

Calculated for C H,N,O,: C, 43.00; H, 2.95; N,

22.80 Found C, 42.77; H, 2.93; N, 22.91

EXAMPLE 2 A. Diazotization of 2-Nitro-p-anisidine To a mixture of 600 g. ice and 220.2 ml. 20 Be.hydrochloric acid is added 104.4 g. real 2-nitro-panisidine. To this chilled solution is added over 15-30 min. 177.6 ml. 25 percent sodium nitrite solution to a positive test on starch iodide indicator paper. The solution is stirred at 0C. for one hour. When diazotization is complete, sulfamic acid is added to a negative test on starch iodide paper. This solution is added to B.

B. Coupling The diazo solution is added gradually at 0 to 5C.

over two hours to a slurry produced by mixing 76.8 g.

real barbituric acid and 208.8 g. sodium acetate buffer with 800 g. ice. The coupling is stirred two hours at C. and then without temperature control until complete.

A stock dye solution is prepared by dissolving 175 mg. dye in 20 to 30 ml. acetone. This is added to a solution prepared by mixing 7 ml. percent sodium lauryl sulfate solution in 100 ml. water at 120F. The volume The product is isolated by filtration and washed with 5 is brought to 350 ml. volume with water 100 to 120F. hot i give 457 8- wet cake; a 8 test Portion A 50 ml. portion of the above dye stock solution is of WhlCl'l dries to 9.0 g- Wh dried at 70 added to 150 ml. water. In the case of dyeing polyes ters, a carrier is used in the dyebath. The amount of EXAMPLE 3 carrier used is 3 ml. of a 50 percent methyl salicylate Dyetests by Thermosol Method 10 aqueous emulsion.

This example shows the application of the new dye to A S-gram skein of fibers of the type mentioned below a polyester fabri by a dry heat fixation th d, T t is introduced. The dyebath is heated to the temperature results of other similar barbituric acid azo dyes are Indicated and ll f for one at that temperature- It given f purposes of comparison is removed and rinsed. Two of the types are -coured,

A 450 mg. sample of the product of Example 1 is disafter f 'f PQlYester l modlfied polyPmpylene' solved with warming in mL N methyl 2 pyrrolidone Scourmg 1S done for 10 minutes at the boil in 0.1 peras solvent. The solution is added to a mixture of 40 ml. neutral Solution followed Then the 10 percent water-soluble dextrin and 40 ml. 10 percent skems are dned' sodium lignin sulfonate. The mixture is homogenized in 20 Same pf F y be followed S'gTam a Waring Blender to produce a dispersion. The disper- Pleces of fabnc Instead of y skeinssion is padded on polyester fabric derived from ethylene-glycol and terephthalic acid using a Butterworth g i gg gfl Temperamre three roll padder to give a pickup of 60 percent and p gg gag; dried in hotair at 160F. for a half hour. Heat of 410F. 3 2;... giflffi gi g is applied for 1.5 minutes. The fabric is rinsed with watnacetate (cellulose tnacetate) Z08 ter, soaped ten minutes at the boil in 0.1 percent neutral soap solution, rinsed with water and dried. A strong uniform yellow shade of good sublimation fastness, rat- A 0,5 percent shade of dye on the weight of the yarn ing 4-5 at 410F. for 30 seconds, is obtained. A com- 30 or fabric is obtained by this procedure.

parison of its shade and strength with other barbituric acid dyes, similarly dyed, is given in Table 1 below.

A comparison of the results on skeins, using this procedure, is given in Table 11.

TABLE II 0.5% shade and strength (est.) Lightlastness rating Subli- Nylon 66 mation (nylon 501), Poly- Nylon Acerating Dye Polyester (Dacron a4) percent Acetate, percent ester 66 tate (contact a Bright Green-Y,100% Y 100 Bright Green-K100..- 6 4 a C5 b V.M. Redder,slightly duller... 100 100 3-4 2 3 1 c Redder and duller 100 100 4 3 3 d Greener 50 4 z 4, 5

No'rE.Lightlastness is determined by AATCC Test Method 16A, 1964 which employs a carbon-l:

amp.

Rating is correlated with hours of exposure needed to produce a slight change in shade. Rating: 2 5 his; 3: 10 hrs.; 4:20 hrs.; 5:40 hrs.; 6:80. In this type of progression, lightfastness is doubled with each inc: unit. Sublimation is determined by sandwiching the dyed polyester skein between cotton and undw l 1' 1 fabric and subjecting the sewn-sandwich to heat of 410 F. for 30 seconds. Any dye sn liming will mm 13 undyed polyester:

TABLE I EXAMPLE 5 Dye Am Combination Blended Dye Composition a. 2-nitro-p-anisidine barbituric acid b. thiobarb tur c ac d A blend is prepared by mixing in .a ball mill and c- Z-methylbarlgrtunc 881g 50 screening. 2- th 'tr il' b m d me my p'm an m 3532213 21.00 parts of the dye of Example 1 Shade Strength 7.80 parts sodium lignosulfonate, dispersant a. bright green-yellow 100% It); 7.80 parts dextrin b. very much redder; 90 0.20 parts sod. 2,4,5-trichlorophenate sesqui-hydrate sl. duller 0.05 arts antifoam 3: 52:52: duller 28: 0.03 parts phenyl mercuric acetate Example 4 Disperse Dyeing Procedure The four dyes described in Example 3 as Dyes a, b, c and d are also applied by the following disperse dyeing procedure.

63.12 water 100.00 parts dye dispersion This blend is suitable for application to fibers by the procedures of Examples 3 and 4.

What 1 claim is:

l. Fibers dyed with the compound 5-(2-nitro-panisylazo) barbituric acid, said fibers being selected from the group consisting of polyethylene terephthalate, nylon and organic esters of cellulose.

2. Cellulose acetate fibers dyed with the compound 5-(2-nitro-p-anisylazo) barbituric acid.

3. Cellulose triacetate fibers dyed with 5-(2-nitro-panisylazo)barbituric acid. 

2. Cellulose acetate fibers dyed with the compound 5-(2-nitro-p-anisylazo) barbituric acid.
 3. Cellulose triacetate fibers dyed with 5-(2-nitro-p-anisylazo)barbituric acid. 